title: Continuous monitoring of ascorbate transport through neuroblastoma cells with a ruthenium oxide hexacyanoferrate modified microelectrode.
abstract: The uptake of ascorbate by neuroblastoma cells using a ruthenium oxide hexacyanoferrate (RuOHCF)-modified carbon fiber disc (CFD) microelectrode (r = 14.5 microm) was investigated. By use of the proposed electrochemical sensor the amperometric determination of ascorbate was performed at 0.0 V in minimum essential medium (MEM, pH = 7.2) with a limit of detection of 25 micromol L(-1). Under the optimum experimental conditions, no interference from MEM constituents and reduced glutathione (used to prevent the oxidation of ascorbate during the experiments) was noticed. The stability of the RuOHCF-modified electrode response was studied by measuring the sensitivity over an extended period of time (120 h), a decrease of around 10% being noticed at the end of the experiment. The rate of ascorbate uptake by control human neuroblastoma SH-SY5Y cells, and cells transfected with wild-type Cu,Zn-superoxide dismutase (SOD WT) or with a mutant typical of familial amyotrophic lateral sclerosis (SOD G93A), was in agreement with the level of oxidative stress in these cells. The usefulness of the RuOHCF-modified microelectrode for in vivo monitoring of ascorbate inside neuroblastoma cells was also demonstrated.
authors.affiliation: Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Thiago R L C
authors.initials: TR
authors.lastname: Paixão
authors.forename: Lívea F
authors.initials: LF
authors.lastname: Barbosa
authors.forename: Maria T
authors.initials: MT
authors.lastname: Carrì
authors.forename: Marisa H G
authors.initials: MH
authors.lastname: Medeiros
authors.forename: Mauro
authors.initials: M
authors.lastname: Bertotti
mesh_terms: D001205:Ascorbic Acid / Q000378:metabolism*; D001692:Biological Transport; D045744:Cell Line, Tumor; D004563:Electrochemistry / Q000379:methods; D005295:Ferrocyanides; D006801:Humans; D008839:Microelectrodes; D009447:Neuroblastoma / Q000378:metabolism*; D010084:Oxidation-Reduction; D012428:Ruthenium
chemical_list: D005295:Ferrocyanides; C116383:ferrocyn; D012428:Ruthenium; D001205:Ascorbic Acid